Temporary masking ceiling

ABSTRACT

Temporary masking ceiling formed by a textile fabric provided with transverse orifices, joined to form open, tubular cavities. 
     The ceiling comprises two identical, superposed sheets (NS, NI), each forming a pattern with polygonal openings, a top sheet (NS) and a bottom sheet (NI), superposed, linked by a curtain of multi-stranded joining yarns ( 10 ) along the sides (C 1 -C 6 ) of the openings (Oi) in order to suspend the bottom sheet (NI) on the top sheet (NS) forming open, vertical cells (Ai).

FIELD OF THE INVENTION

This invention relates to a temporary masking ceiling formed by a textile fabric with transverse orifices joined to form open tubular cavities.

PRIOR ART

For the most part, temporary, commercial or cultural exhibitions are set up in specialised, very tall halls of an industrial nature under beams, because they must be able to accommodate a whole variety of products for human activity. Their industrial appearance is accentuated by fixed lighting means, always located very high up, which means that they glare and are thus unsuitable for exhibiting refined objects of human size, such as consumer goods or cultural items. Such exhibitions are the most frequent type.

It is therefore often necessary to transform the appearance of these halls in order to adapt them aesthetically and sometimes technically to the nature of the exhibition in question. Specialised architects are called in to design them and stand or exhibition fitters set them up.

These professionals use techniques which are associated with building work but very specialised due to the specific conditions of how they are used. Of these techniques, those involving temporary masking ceilings are the most important and the most complex.

These ceilings comprising flat sheets which are suspended and tautened contribute to the three actions of:

-   -   masking the hall roofs and their industrial equipment from the         view of visitors, thereby eliminating all unsightly views,     -   enabling aesthetic exhibition spaces to be created, in tune with         both the dimensions and the nature of the objects exhibited,     -   enabling lighting systems to be created which are in tune with         the exhibited products. This operation involves either         neutralising the glaring effects of the fixed lighting systems         by diffusing them or integrating new lighting systems which         neutralise and/or diffuse the fixed lighting systems.

As a result of these operations, the ceilings mask and eclipse whatever fixed, artificial or natural lighting sources there might be in the halls to varying degrees.

In addition to having to satisfy these basic functions at the installation site, these ceilings must also conform to safety regulations as a matter of course, i.e.:

-   -   be sufficiently fire resistant in the event of potential fires,     -   enable fumes to be evacuated due to their vertical permeability,     -   permit the operation of automatic extinguisher devices which         sprinkle down from above.

Temporary ceilings are based on two technical principles.

First Principle

This first principle involves providing horizontally continuous sheets made from textile by juxtaposing panels assembled by separator lines in the form of fusible yarns.

Such ceilings are described in documents FR 88 15 966 and FR 89 13 328 CHENEL, for example.

Special yarns, generally made from polyamide, are used for this purpose, the melting point of which is lower than the temperature at which spray nozzles are triggered, i.e. 80° C. Since, by nature, tense textiles are elastic and held tautened in the fitted state, they come apart when rising fumes reach them during a fire.

The fire-resistant elements come apart due to shrinkage caused by the melting of the special yarns joining them. The hot fumes then escape upwards and are eventually evacuated via automatic extractors activated by the increase in temperature. In the same way, these hot fumes can then also trigger the spray nozzles on reaching them.

It should be pointed out that these textiles are sufficiently permeable to liquids for the jets from the nozzles to be able to reach the sources of fire which they overhang. The “mesh” technique is used to make these textiles, which is the only way of separating two panels from the same sheet. In practice, conventional fabrics made by weaving warp and weft yarns do not allow such a join incorporating fusible yarns unless the sheets are made by juxtaposing separate woven panels and stitching them to one another by means of fusible yarns.

A masking and also more or less eclipsing effect can be easily imparted to ceilings based on the first principle depending on their density and their colour, although this technique is less economical.

Second Principle

This second principle makes use of a peculiar trait of human beings and in particular exhibition visitors. For the most part, the latter direct their vision along an axis that is close to the horizontal. More specifically, this vision is contained in a cone of the horizontal axis, the apex of which is normally situated in the middle of the segment linking the two eyes and the highest generatrix of which delimits the upper field of clear vision.

Only the highest generatrix must be taken into account when looking for ways of masking a ceiling. This cone of clear vision is more contracted than the optimum cone of global indistinct vision for which allowance has to be made in defining the masking ability of a temporary ceiling. The difference in opening between these two cones is necessary for the visitor's visual comfort, since it is what gives him the indistinct visual environment. From experience, the angle α of the upper generatrix of the optimum cone of indistinct vision measures an angle of approximately 25°, vertically, above the horizontal.

In the case of this second principle, the masking elements are vertical and constitute cellular, cylindrical walls with closed sections of various shapes. These vertical elements interrupt all vision with an angle of less than 25° above the horizontal direction.

FIGS. 1 and 2 illustrate the principle of this technique of three-dimensional false ceilings (false 3d ceilings).

FIG. 1 is a vertical section illustrating the principle of the horizontal section (FIG. 2) along CD. A flat sheet of a false ceiling is illustrated, horizontally, in front of and higher than the observer located at A. This false ceiling of netting is made up of thin vertical masking strips.

The normal vision of a spectator located on a horizontal surface is directed horizontally for the most part and falls within a cone, the apex of which is horizontal and perpendicular to the middle of the segment linking the two eyes of the spectator. This cone has an opening of 30° vertically (FIG. 1) and 60° horizontally (FIG. 2). The bottom face of the false ceiling for the spectator located at A will afford a full masking effect from the point 1/1 and beyond. Point 1/1 represents the start of clear vision for the observer located at A (apex of the cone of vision); if, unusually, the observer raises his head, the ceiling will no longer appear to produce a full masking effect between point 1/1 and the portion of space located above him. This is of little importance because the spectator will retain the impression of having visited an exhibition with a masking surface that is continuous across its entire surface. This peculiarity of visual memory associated with human behaviour is exploited in this design and implementation of three-dimensional false ceilings (false 3D ceilings). In exceptional situations, the angle α may be different from the usual angle of 15° depending on the need for upward or downward vision in order to observe large objects.

For the observer located at A, FIG. 1 illustrates the horizontal plane of normal vision, at which point the cones axes delimits normal vision. Below this plane, the line AF represents the lower limit of the cone of clear vision (or solid angle) if the observer pivots about his vertical axis A′A′.

Above the horizontal plane, line AG represents the upper line of the cone of normal clear vision from point A. This AG line has already been described. Above line AG is a partially masked zone for a pivoting movement by the observer about his vertical axis A′A′ corresponding to a cone of distinct or clear non-perception, with an opening of 120°. This cone of clear non-vision follows the visitor and defines, a contrario, the upper limits of normal clear vision.

The characteristics of a false 3D ceiling which permits masking for the directions of clear vision have been described, i.e. for the upper generatrices of cones with horizontal axes subtending 15° with the axes. In practice, the tendency will be to opt for cones of vision measuring approximately 25° above the horizontal in order to satisfy indistinct visions which correspond to the comfort of exhibition visits, the upper generatrix of the cone being the straight line AJ (FIG. 1).

In FIGS. 1 and 2, the square cells of the false ceiling are shown diagonally with respect to the spectator's axis of vision. This disposition is the least conducive to masking, although the spectator positioned at B enjoys more favourable masking.

The technique described above is based on two main principles:

-   -   1—It enables sheets that are very permeable to vertical flows to         be produced because it is easy to reduce the thickness of the         horizontal elements.     -   2—Its masking capacity is based on the formula h≧D Tgα, where h         is the vertical height of the cell and D the longest diagonal of         the cell base. Since Tg 25°=0.46 when h is equal to about half         of D, a masking sheet will be obtained.     -   Since this relationship between the horizontal opening of the         cell and the vertical height of the walls is an angular         relationship, it is possible to make masking ceilings based on         this technique with a very broad range of options for varying         the cell dimensions. The choice will depend on the size of the         premises to be covered, the materials used and the sought         effects, as well as economy.     -   By way of example, therefore, it is possible to make sheets in         which the cell openings vary from a few millimetres to several         tens of metres, in which case the height of the cells always         varies in keeping with the equation h # D/2.

Such a masking ceiling is described in document FR 04 52 836 CHENEL, for example.

There are also different designs of three-dimensional masking ceilings as disclosed by document WO99/34070 SCHALÜCK.

This document describes a textile masking sheet formed by a network of crossed tension yarns (weft yarns and warp yarns) 2, 3 bearing short yarns or ribbons 4 which hang. The tension yarns 2, 3 define the section of sheet 1's openings. This section is theoretically sufficient for the water from sprinkler nozzles to pass through the openings 5 in the event of fire. However, this structure and its different variants have the disadvantage of being difficult to make and in particular to fit as a tensed ceiling. Furthermore, the masking effect cannot be produced easily and in a guaranteed manner because the yarns must hang freely in order to form the cells creating the masking effect. These yarns may become tangled when the sheet is unrolled and remain so after fitting or even become tangled due to the effect of circulating air after fitting. The resultant masking effect is uncertain and, depending on the circumstances, the opening of the orifices needed to permit a passage for sprinkled products from the fire protection nozzles may not be sufficient and may not conform to regulations.

OBJECTIVE OF THE INVENTION

The objective of this invention is to propose a temporary masking ceiling which is easy to produce and install and which will reliably ensure an excellent masking effect whilst remaining permeable.

DESCRIPTION AND ADVANTAGES OF THE INVENTION

To this end, the invention proposes a masking ceiling of the type defined above, characterised in that it is made up of two identical superposed sheets, each forming a pattern of polygonal openings,

-   -   a top sheet and a bottom sheet, superposed,     -   linked by a curtain of multi-stranded joining yarns along the         sides of the openings in order to suspend the lower sheet on the         upper sheet to form open vertical cells.

The resultant masking ceiling has a number of advantages because it produces a sufficient and regular masking effect irrespective of the direction of the visitor's usual vision, i.e. irrespective of the orientation of the axis of the visitor's cone of vision relative to the orientation of the cell openings formed by the sheets and the curtains of yarns. This ceiling satisfies safety conditions because it permits a rate of vertical permeability greater than 55%, i.e. a ratio of empty surfaces to solid surfaces. The opening of the cells is not at risk of being blocked by the joining yarns because they are tensed by the bottom sheet where they mutually provide the suspension for the bottom sheet on the bottom sheet. Under these circumstances, the joining yarns are perfectly vertical due to their flexibility and their lack of rigidity. This latter quality is important because if they were to exhibit rigidity due to the fact that they can be fitted obliquely relative to the sheets, this would result in an offset arrangement of the cells.

The manufactured sheet is very light. For a thickness in the order of 5 to 6 mm, it weighs approximately 130 g/m² in the tensed state. This ceiling can advantageously be packaged in relatively short rolls, taking account of the high capacity to stretch in the direction of the weft, i.e. in the direction of the width of the rolls or perpendicular to the length of the rolls.

For installation, tensed strips may be used, which are essentially twice as wide as the width of the fabric in its relaxed state.

The advantage of the product is that it can be manufactured in large sheets and assembled by stitching.

The sheet is particularly easy to install.

The aesthetic appearance of the sheet may also be highlighted. It may be dyed or printed.

As a result of one advantageous feature, the section of the openings is close to that of a circle.

Very advantageously, the openings section is hexagonal.

As a result of another feature, the yarns of the sheets are textured, i.e. elastic and bulky.

This feature enables the top and bottom fabrics and, on this basis, the dimensions of the cell openings to be made bigger by stretching, whereas the joining yarns do not stretch and naturally move into a position perpendicular to the two fabrics.

DRAWINGS

The invention will be described in more detail below with reference to the appended drawings, of which:

FIGS. 1 and 2 are diagrams illustrating the operating principle of a masking ceiling,

FIG. 3 is a view from above on a very much enlarged scale showing a pattern of a temporary masking ceiling proposed by the invention,

FIG. 4 is a view in section along IV IV of the temporary masking ceiling illustrated in FIG. 3,

FIG. 5 is a perspective view of a cell.

DESCRIPTION OF THE INVENTION

As illustrated in FIGS. 3 and 4, the invention relates to a temporary masking ceiling comprising a textile fabric provided with transverse orifices, joined so as to be permeable on the basis of a ratio of permeability defined by safety regulations; it corresponds to the ratio between the open surface and the opaque surface. The fabric is masking in the sense of the definition given above, i.e. the height of the cells and the biggest dimension of the section of the cells conform to the masking ratio or angle.

The fabric 1 is horizontally tensed in the two directions X, Y of its plane (FIG. 2) and is made up of joined cells with a thickness in the vertical direction Z (FIG. 4).

An example of a cell pattern is illustrated in FIGS. 3 and 4 in a frame surrounded by a broken line. The pattern corresponds to a hexagonal cell section, which is also illustrated in perspective in FIG. 5.

As illustrated in FIGS. 3 and 4, the fabric is made up of a top sheet NS and a bottom sheet NI, superposed. The two sheets have the same geometry of openings O and are superposed exactly, linked by curtains of joining yarns 10 along the sides C1-C6 of the openings Oi. Sheets NS and NI are made from textured yarns, i.e. yarns which are elastic and bulky when relaxed. The joining yarns 10 are multi-stranded and very flexible.

The fabric unit 1 comprising the top sheet NS, the bottom sheet NI and the joining yarns 10 is made in one operation.

The fitted fabric 1 forms a thin but three-dimensional (3D) structure (FIG. 4) from the point of view of the masking effect with cells Ai of a hexagonal section (FIG. 4) corresponding to the pattern of the polygonal openings Oi, delimited by the curtains of vertical joining yarns 10 forming the walls of the cells Ai.

In one embodiment, the hexagonal openings Ai have a diagonal of 6 mm and the NS and NI sheets are spaced apart by a distance of 3 mm. 

1) Temporary masking ceiling formed by a textile provided with transverse orifices, joined to form open tubular cavities, characterised in that it is made up of two identical superposed sheets (NS, NI), each forming a pattern with polygonal openings, a top sheet (NS) and a bottom sheet (NI), superposed, linked by a curtain of multi-stranded joining yarns (10) along the sides (C1-C6) of the openings (Oi) in order to suspend the bottom sheet (NI) on the top sheet (NS) forming open vertical cells (Ai). 2) Masking ceiling as claimed in claim 1, characterised in that the section of the openings (Oi) is hexagonal. 3) Masking ceiling as claimed in claim 1, characterised in that the section of the openings is close to that of a circle. 4) Masking ceiling as claimed in claim 1, characterised in that the yarns of the sheets (NS, NI) are textured. 